1. Field of the Invention
The field of the invention relates to systems which supply a fuel-air mixture into the combustion chamber(s) of an internal combustion engine.
2. Description of the Prior Art
For fuel efficiency, it is desirable to introduce a high amount of fuel-air charge into a cylinder for combustion. It is also desirable for fuel efficiency that a high proportion of the fuel introduced into the cylinder is evaporated rather than in liquid form.
Some systems of the prior art have been designed to introduce a high amount of fuel-air charge by incorporating various means of cooling the air or air-fuel mixture. A cooler fuel-air mixture results in a denser charge and thus more charge can be introduced. For instance, U.S. Pat. No. 4,155,337 to Hensly discloses a mechanical refrigeration system for cooling fuel prior to being inducted into the carburetor. Other systems have pre-cooled the air. by the introduction of this denser air into the combustion chamber a greater charge is provided and more oxygen is supplied so that there is more complete combustion.
Another system which cools the fuel-air mixture prior to introduction into a combustion chamber is disclosed by U.S. Pat. No. 4,165,720 to Barcak. According to this patent, a water jacket surrounds the intake manifold to cool the fuel-air mixture prior to entering into the combustion chamber, thus allowing a greater change to be introduced. U.S. Pat. No. 4,159,698 to Berenbaum discloses yet another system which incorporates a pre-cooling feature. According to the Berenbaum patent, an ordinary carburetion system is used in connection with an evaporation chamber. Fuel is vaporized in the evaporation chamber under a vacuum and the resulting cooled fuel-air mixture is introduced to the internal combustion engine downstream of the carburetor.
A typical problem with systems that involve cooling is that the fuel tends not to be fully vaporized, thus combustion is inhibited. It has been postulated that by heating the fuel-air mixture, a more completely vaporized fuel may be introduced into the combustion chambers of the engine. See U.S. Pat. No. 3,892,211 to Oyama, which discloses a system which both pre-heats, and then pre-cools the fuel air mixture prior to introduction into a combustion chamber.